A Whirlpool Duet horizontal-axis washer and propane-fired dryer make efficient work of laundry with less load on the batteries.

A Bosch propane on-demand water heater serves the home.

The OutBack VFX3524 inverter and balance-of-system components.

The eight Deka L-16s provide 740 Ah at 24 VDC.

System designer Kurt Nelson (left) with Sally and Jerry under the array.

Intermediate

In 2009, when Sally and Jerry Bowker retired to their property in Bayfield County, Wisconsin, living off-grid was not new to them. In the 1970s and early ’80s, they lived without electricity on a 100-acre homestead in western Wisconsin. Although they’d subsequently lived in a conventionally powered home, upon retiring, they wanted to build an off-grid home in the woods of northern Wisconsin. In 2004, they found 10 wooded acres near the south shore of Lake Superior. In 2007, they built a small studio there, along with a small PV system, and made plans to build an off-grid home.

Most of Bayfield County is public forestlands, and these extensive natural areas are great for recreation. Jerry and Sally help maintain the Apostle Islands National Lakeshore mainland trail that runs close to their homestead. Many people living in the area understand that they are an element of nature that needs to find its harmonious path within the larger natural system. This cultural mindset, as well as the area’s natural beauty, was the couple’s primary attraction to the region.

Sally is an art photographer, focusing on nature. Jerry also has an art background, and enjoys applying his aesthetic sense to the areas around their homestead. Ecologist Aldo Leopold was an early inspiration for merging the natural world with his intellectual life as an environmental philosopher and professor at the University of Wisconsin.

Thoughtful Design

Sally took on the home’s design, working with designer-architect Kristine Recker and studying Christopher Alexander’s A Pattern Language, which was based on the idea that “people should design for themselves their own houses...”

The house fits the couple’s specific pattern of living, with the kitchen and the wood heater in the center of the house. The main rooms are multiuse and sized to accommodate 95% of their everyday activities. For example, the sunroom also serves as a library and guest bedroom, with bookshelves on three sides and a sofa bed. It also is an art studio, with a loom and weaving supplies. Its deep windowsills are used for growing flats of seedlings in the spring. The center room is a gathering space, with chairs by the wood heater, pet beds, and a table for dining or projects. Here, a window seat holds bedding for the guest bed. Their home office, with desk and files and computer, is also here. The computer and a photo printer form a studio for photography work in this space. The PV balance-of-system equipment, along with a freezer, a washer-dryer, utility sink, and toilet occupy the utility room. The entry to the crawl space is here as well. The crawl space holds the water pressure tank, the PV system’s batteries, home canning storage, and is used as a root cellar for garden crops.

The 1,200 square-foot home’s longer axis was oriented to take advantage of winter solar gain, with well-sized windows to the south and west admitting solar gain and reducing the home’s reliance on wood heat. Adequate overhangs shade the windows in summer. The home’s builder, Jim Steffenson of Steffenson Carpentry, had built his own passive solar, off-grid home. Jim and solar-electric installer Kurt Nelson of SOLutions in Cornucopia, Wisconsin, coordinated plans for reducing the building’s ecological and energy footprint, and incorporating the solar electrical requirements during the home’s construction.

To provide ample insulation for the northern home, the walls are double-stud construction. The 9.5-inch-thick walls were filled with blown-in cellulose insulation, resulting in an R-value of about 33.

Comments (6)

Sally & Jerry,
Congrats on the successful adaptation of your RE system to your lifestyle (and vise versa). Would you care to share your philosophy with the microwave and using a separate freezer and fridge? Thanks, Bill

I'm wondering how their MX60 charge controller is holding up, what with 2100 watts of PV for a 24V battery system. Normally (I thought, anyway) for a 24V system the MX60 can't use more than about 1500 watts of PV (24V x 60A = 1440W). I'm asking because I have an MX60 and am currently considering adding PV but was going to go the added CC route, since I'm already near my MX60's max power input for my 24V system.

If I where to upgrade my solar today, I would not spend $500 on a MPPT controller. The 40 amp Schneider controller at SunElec.com (a long time advertiser here) is only about $125. 250-300 watt panels can be bought for less than $200 now. So I would spend more on panels, not the controller. Another slightly risky thought would be to have two panels with just a on-off switch. 10 extra amps going into the battery anytime the sun shines. It might slightly overcharge your battery if you don't have afternoon loads, the main controller has shut off. But if the battery is not getting full every day, or you have a constant 5 amp average load, you will not have a problem, (with late afternoon overcharging) as long as you shut off the extra panel in summer or while on vacation.

Yes I have a SB 50 MPPT controller in my motorhome 415 watt solar system. That system cost $3000 in the 90's, and could be replaced for about $800 today.

the (now discontinued) mx60 can be set for 70 amps, which means it will process around 72 amps before "de-optimizing" the mppt tracking at this limit. 72 amps X 52 volts = 3.7 kW. mine has processed this amount of power for over 10 years with no problems (on a 24 volt system, this would be 72 X 26 = 1.8 kW).

Not to beat a dead horse but the system in the article is 24volts with 2100 watts of PV. Although the MX60 WILL run up to 70A output, seems like frequent operation at the MX60's max rating would shorten its life. Thus my original question.

I guess perhaps the short answer is, if there had been any problems this article would have read differently.

the mx60 will off track the mppt to protect itself. in addition it will shut down if "too hot" (fan failure). outback would not have designed a charge controller designed to fail when operated within the allowable software parameters. these things are very robust!